Re-entrancy of flash erase/write
awozniak at comdev.cc
Mon Feb 25 10:44:21 EST 2002
On Mon, 25 Feb 2002, Robert Kaiser wrote:
> I looked into this a little further: it seems that the erase
> functions in cfi_cmdset_000?.c and amd_flash.c temporarily release
> the chip->mutex while VPP is on. Won't that allow other threads
> to get hold of the mutex and fiddle with VPP, possibly turning it
> off ?
> That would explain the behavior I'm observing here. Only why doensn't
> anyone else see this problem ?
> A proper solution IMHO would be to use a counter (similar to what I
> now have in my mapping driver) in the ENABLE/DISABLE_VPP() macros.
If I recall correctly, last time I dug into this:
ENABLE/DISABLE_VPP call the map_info set_vpp function
For the physmap_map map_info, there is no set_vpp, it is NULL
So for people who use physmap_map anyway, they won't see the behavior
you are describing. I suspect it is the same for other maps.
Adam Wozniak (KG6GZR) COM DEV Broadband - Digital and Software Systems
awozniak at comdev.cc 805 Aerovista Place, San Luis Obispo, CA 93401
Voice: (805) 544-1089 Fax: (805) 544-2055
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